Adjustable pivoting cradle for large caliber guns

ABSTRACT

In order to increase the firing stability of a gun mount wherein a traversing carriage is rotatably supported on a stationary firing platform, the recoiling parts of the gun are slidably housed in a cradle formed by an outer frame pivoted in the carriage and an inner frame slidably seated in the outer frame to extend substantially rearward of the pivot point of the latter, the cradle also including means responsive to changes in the elevation angle of the gun for relocating the center of gravity of the cradle relative to the central vertical axis of the firing platform to minimize the overturning movement thereof during the firing of the gun.

[ Sept. 18, W73

ADJUSTABLE PIVOTING CRADLE FOR LARGE CALIBER GUNS Frederick S. Schrage, Rock Island, Ill.

Assignee: The United States of America as represented by the Secretary of the Army, Washington, DC.

Filed: Dec. 14, 1970 Appl. No.2 97,644

lnventor:

US. Cl. 89/37 R, 89/41 R Int. Cl F4lf 21/04 Field of Search 89/37 R, 37 A, 37 F,

89/37 GM, 40 R, 41 R, 42 B, 43 A References Cited UNITED STATES PATENTS FOREIGN PATENTS OR APPLICATIONS 278,356 6/1928 Great Britain 89/37 A Primary Examiner-Stephen C. Bentley Attorney-Harry M. Saragovitz, Edward J. Kelly, Herbert Berl and Albert E. Arnold, Jr.

[57] ABSTRACT In order to increase the firing stability of a gun mount wherein a traversing carriage is rotatably supported on a stationary firing platform, the recoiling parts of the gun are slidably housed in a cradle formed by an outer frame pivoted in the carriage and an inner frame slidably seated in the outer frame to extend substantially rearward of the pivot point of the latter, the cradle also including means responsive to changes in the elevation angle of the gun for relocating the center of gravity of the cradle relative to the central vertical axis of the firing platform to minimize the overturning movement thereof during the firing of the gun.

2 Claims, 5 Drawing Figures T nsm 81973 3,759,138

sum 1 or 3 INVENTOR Frederick E1 EtfhbujE ATTORNEYS PATENTED SEP! 8 I875 SHEET 2 UF 3 Em O 8 E E m 5 E Y N W 5 m E T Wm Wm B E a. E B

HHH ll llllll PATENTED 81975 3.759.138

sum 3 0F 3 INVENTOR FEE fienick E -Edmugk ATTOR NEYS L ADJUSTABLE PIVOTING CRADLE FOR LARGE CALIBER GUNS BACKGROUND OF THE INVENTION This invention relates to the mounting of large caliber guns and is more particularly directed to a pivotal cradle for supporting the recoiling parts of the gun in a manner which will increase the stability thereof during firing, especially at the higher elevation thereof.

The emplacement of artillery in firing position is generally complicated by the necessity for firmly anchoring the firing base or platform to counteract the tendency thereof to tilt or dig into the ground under the influence of the forces imparted thereto during the firing. These anchoring problems essentially result from the fact that the center of gravity of the gun cradle is generally remotely disposed with respect to the central vertical axis of the firing platform.

While numerous design efforts have been made to reduce the mass of the firing platform and to eliminate the customary elongated trail structure without incurring a corresponding decrease in the firing stability of the gun, none of these prior efforts are known to have met with any significant success. For example, it has been proposed that the cradle utilized to support the recoiling parts of the gun be substantially centrally mounted in the carriage to minimize the moment arm between the center of gravity of the recoiling parts and the trunnions on the cradle. While such relationship does provide a substantial reduction in the tendency for the firing platform to shift position under the influence of the forces imparted thereto during firing, the required relocation of the cradle in the carriage positions the rear end of the former considerably to the rear of the trunnions thereon thereby curtailing the degree to which the recoiling parts can be elevated for firing without striking the ground. Since the height at which the cradle is mounted in the gun carriage cannot be increased without a compensatory increase in the vertical dimension of the firing platform to maintain the required firing stability, the problem has heretofore been solved by digging a pit in the ground to accommodate the rearward travel of the recoiling parts at maximum firing elevation. Obviously, the additional time and effort required to incorporate the digging of a pit in the procedure for emplacing the gun in firing position will completely nullify the advantages achieved by a decrease in the size and weight of the firing platform.

Accordingly, it is an object of this invention to provide a relatively simple and reliable mounting arrangement for large caliber guns wherein'the size and weight of the firing platform therefor can be considerably reduced over that required in conventional mounts without any significant reduction in the firing stability of the gun.

It is a further object of this invention to provide a pivotal cradle for supporting the recoiling parts of the gun in a mount, as aforesaid, wherein the rear end of such cradle extends considerably rearward of the trunnions thereon without the need for. a pit in the ground to accommodate the breech end of the gun tube when firing at maximum elevation.

Another object of the present invention resides in the thereby increasing the stability thereof in all the firing positions to which the gun is elevated.

An additional object of this invention is to provide a cradle, as aforesaid, wherein changes in the firing clcvation of the gun will relocate the center of gravity of the cradle together with the recoiling parts supported thereby along an involute path relative to the trunmons.

SUMMARY OF THE INVENTION It has been found that the foregoing objects can be accomplished by supporting the recoiling parts of the gun in a cradle arranged to extend considerably to the rear of the trunnions thereon. Such cradle is also divided into an outer frame to which the trunnions are secured and an inner frame slidably dovetailed in the outer frame to serve as the support for the recoiling parts of the gun. The underside of the inner frame is preferably provided with a pair of spaced parallel gear racks, each in meshing engagement with twin pinions included in a gear train supported on each of the opposite sides of the traversing carriage in which the cradle is pivotally mounted. Each gear train also includes a gear in engagement with suitable teeth on the fixed elevating arcs which extend upwardly from the carriage. Both gear trains are arranged to be simultaneously driven in the same direction by a handwheel rotatably mounted in one side of the carriage.

Rotation of such handwheel in either direction pivots the entire cradle about the trunnions thereon to position the gun tube and the other recoiling parts associated therewith to the desired firing elevation. As the cradle is thus pivoted, the gear trains in each side of the carriage also function to displace the inner frame of the cradle relative to the outer frame along an axis parallel to the longitudinal axis of the recoiling parts. Such displacement of the inner frame prevents the recoiling parts from striking the firing platform or the ground when the gun is being operated at the higher elevations thereof. In addition, the combined pivotal and longitudinal movement of the inner frame during changes in the firing elevation of the gun causes the center of gravity of the cradle together with the recoiling parts supported thereby to follow an involute path relative to the trunnions. As a result, the center of gravity of the cradle together with the recoiling parts is located relatively close to the central vertical axis of the firing platform on which the carriage is rotatably supported thereby significantly increasing the stability of the gun during the firing thereof, especially at higher elevations.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a large caliber gun pro-- vided with the self-adjusting cradle of the present invention, the full lines showing the gun in a horizontal firing position and the broken section lines showing the change in location of the center of gravity as the gun is pivoted toward a position of maximum elevation;

FIG. 2 is an enlarged front end view of the cradle structure of FIG. ll;

FlG. 3 is a section taken along lines 3-3 of FllG. I to show the connection between the worm gear assembly and the gear train on one side of the inner frame of the cradle;

FIG. 4 is a section taken along line 44l in FIG. 2 and enlarged to illustrate the structural detail of one of the gear trains which pivot the cradle to provide the desired elevation of the gun; and

FIG. 5 is a section taken along line 5-5 in FIG. 2 to illustrate the structural detail of the worm gear assembly utilized to convert the rotation of the handwheel to actuation of the gear trains.

DESCRIPTION OF A PREFERRED EMBODIMENT In large caliber guns which must be mounted on a stationary firing platform so as to present a minimum silhouette, the cradle is generally provided with trunnions at the extreme rear end thereof for rotatable engagement in the rear end of the carriage which is, in turn, supported on the firing platform for 360 traverse. Since the recoiling parts of the gun must be adequately supported by the cradle, the latter is customarily extended forwardly to a considerable extent. As a result, the center of gravity of the cradle together with the recoiling parts, hereinafter referred to as the tipping parts, is located considerably forward of the central vertical axis of the firing platform thereby creating a relatively long moment arm. In order to counteract the overturning effect of this moment arm, the firing platform is usually constructed to be fairly massive in size or instead, is provided with an elongated forward extension in contact with the ground for properly supporting the tipping parts when the gun is fired at 0 elevation. In addition, the firing platform is also customarily provided with an elongated trail structure extending sufficiently rearwardly therefrom to counteract the forces imparted to thegun during the firing thereof at the higher elevations. Obviously, if the required firing stability of the gun is achieved by increasing the size and weight of the firing platform, the required ease of transportation will be adversely affected. On the other hand, if the need for additional firing stability is attained by adding a forward extension and a rearward trail structure to the firing platform, the required ease of handling and servicing during the firing operation thereof will be reduced to an unacceptable extent.

These drawbacks of prior art mounts can be eliminated, or at least drastically reduced, by a two-piece cradle 26 consisting of an inner frame 28 in slidable engagement with an outer frame 32. Inner frame 28 is preferably of tubular configuration, as best shown in FIG. 2, and is open along the top thereof, as at 34, to slidably house and support a gun tube 16 and the recoiling parts 18 associated therewith. A generally rectangular slide 36 is fixedly secured, as by screws 38,to each of the opposite sides of inner frame 28 in diametrically opposed relation and is provided with an outwardly facing channel 40 of dovetail configuration for slidably receiving a mating dovetail segment 42 projecting from the corresponding side of outer frame 32.

In order to secure the required rigidity of structure,

outer frame 32 is preferably formed by opposing sideplates 44 with the dovetail segments 42 projecting inwardly and integrally from the upper portions thereof. In addition, the lower portions of sideplates 44 are connected by a bracket 46 extending beneath inner frame 28. Sideplates 44 are pivotally supported in generally rectangular upright members 50 which are, in turn, fastened at the lower ends thereof, as by screws 52, to a circular base 54 arranged to be mounted on a stationary firing platform 55, as best shown in FIG. 1. Support members 50 are suitably braced, as indicated at 56, to serve as the sidewalls of a carriage 58 rotatably mounted on platform 55 for 360 traverse. Projecting outwardly from the outer face of each sideplate 44 at a location slightly rearwardly of the central vertical axis of firing platform 55 is a preferably integral trunnion pin 60 of sufficient length to fully seat in a semicircular recess 62 formed in the top edge of carriage sidewall 50. As best shown in FIG. 1, trunnion pins 60 are rotatably retained in recess 62 by suitable clamps 64.

Forwardly of trunnion pin 60, each carriage sidewall 50 is upwardly extended, as indicated at 66, to include an elongated arcuate clearance slot 68 formed transversely therethrough about trunnion pin 60 as a center. The inner face of each carriage sidewall 50 is also transversely channeled, as indicated at 70, coextensive with but to a greater width than slot 68 to house a correspondingly arcuate gear rack 72 which is fastened thereto by bolts 73 so that the teeth thereof are disposed forwardly of and in arcuate alignment with the forward wall of slot 68. In meshing engagement with rack 72 is a pinion gear 74 (FIG. 2) which is pinned to one end of an elongated shaft 78 journaled in the lower ends of side plates 44. Gear 74 is positioned so that the hub end thereof is in bearing abutment with the outer face of sideplate 44. A spur gear 80 similar to gear 74 is also pinned to shaft 78 on the other side of sideplate 44 in bearing abutment with the inner face thereof.

A driving gear 84 is pinned to one end of a shaft 88 journaled in a gear housing 90 which is, in turn, fixedly secured to the left-hand sideplate 44 of outer frame 32 as viewed in FIG. 2. Gear housing 90 consists ofa substantially rectangular hollow portion 92 having a tubular section 94 extending outwardly therefrom to terminate in an enlarged end flange 96 which is fastened to the outer face of sideplate 44 by a plurality of radially disposed screws 98. Tubular section 94 of housing 90 is of sufficient length to extend transversely through arcuate clearance slot 68 in sidewall 50 and position rectangular portion 92 outwardly thereof. The upper portion of gear housing 90 is rearwardly extended at right angles to tubular section 94 to terminate in a yoke 99.

Driving gear shaft 88 extends through tubular section 94 of housing 90 into the interior of rectangular portion 92 to terminate in a worm gear 100 pinned thereto, as indicated at 102, in FIG. 3, in meshing engagement with a worm 104. The latter is, in turn, pinned to a shaft 108 which is transversely journaled in the upper end of rectangular portion 92 of gear housing 90 to extend therefrom into the area encompassed by yoke 99. An axle 1114 is rotatably supported between the arms of yoke 99 and extends outwardly therefrom to provide a fixed support for a handwheel 116. Rotation of handwheel 116 is transmitted to worm 104 by a miter bevel gear 118 pinned to axle 114 within the arms of yoke 99 and in meshing engagement with an identical bevel gear 120 pinned to the adjacent end of shaft 108.

Immediately above driving gear 84 and in simultaneous meshing engagement therewith are a pair of Iongitudinally spaced spur or pinion gears 122 also in meshing engagement with one of a pair of spaced parallel gear racks 124 extending longitudinally along the underside of inner frame 28. Spur gears 122 are mounted on shafts 126 correspondingly located in the left-hand sideplate 44 of FIG. 2 to project from the inner face thereof. A similar gear train is provided on the right-hand sideplate 44 in the same meshing engagement with racks 72 and 124 except that the driving actuation of this gear train is accomplished by spur gear 80 rather than by the intermediate spur gear 84 as in the train on the left-hand sideplate 44.

In order to elevate cradle 26 and bring gun tube 16 to the desired firing attitude, handwheel 116 is rotated in a clockwise direction, as viewed in FIG. 1, to impart corresponding rotation to worm 104 and worm gear 100 thereby actuating driving gear 84 to rotate spur gears 80 in both sides of carriage 58. in view of the meshing engagement between pinion gears 74 and fixed elevating racks 72, outer frame 32 of cradle 26 is pivoted about trunnion pins 60 and carries inner frame 28 together therewith as tubular section 94 of gear housing 90 passes freely along the length of clearance slot 68.

However, since driving gear 84 is also in meshing engagement with gears 122 which are, in turn, engaged with linear gear racks 124, inner frame 28 is longitudinally displaced relative to outer frame 32 simultaneously with the pivotal movement of cradle 26. This movement of inner frame 28 changes the location of the center of gravity of the tipping parts along an involute path relative to trunnion pins 60 in accordance with the degree to which cradle 26 is pivoted to elevate the gun. Thus, while the tilting of cradle 26 during the elevation of the gun brings the breech end of the recoiling parts 16 and 18 closer to the ground, this movement is offset by the opposing movement imparted to inner frame 28 of cradle 26 by spur gears 122 thereby maintaining the distance required to prevent the breech end of gun tube 16 from hitting the ground during the recoil travel thereof. Furthermore, the combined pivotal and longitudinal movement of inner frame 28 of cradle 26 minimizes the horizontal displacement of the center of gravity of the tipping parts relative to the vertical axis through the center of firing platform 12 as shown in FIG. 1. As a result, the overturning movement imparted to the gun by the recoil forces encountered during firing, especially at the higher elevations thereof, will be significantly reduced thereby permitting a considerable reduction in the size and weight of firing platform 55 as well as in carriage 58. Obviously, the smaller the area occupied by the entire mount, the easier for the operating personnel to emplace, load and service the gun. At the same time, any appreciable reduction in the weight of the mount also increases the mobility of the gun.

Although the present invention is explained in accordance with the preferred embodiment shown and described herein, it will also become obvious to persons skilled in the art that other forms thereof, as well as changes in the particular forms described, are possible within the spirit and scope of the present invention. Therefore, it is desired that the present invention shall not be limited except insofar as it is made necessary by the .prior art and by the spirit of the appended claims.

I claim:

l. A cradle for pivotally supporting the recoiling parts of a gun between a pair of spaced arcuate gear racks on a stationary mount, said cradle comprising,

an outer frame having trunnions on each sidev thereof inpivotal engagement in the gun mount,

an inner frame having a longitudinal gear rack along each side thereof,

means for slidably seating said inner frame in said outer frame to support the recoiling parts of the gun centrally between said trunnions, said outer frame extending rearwardly beyond said trunnions and said inner frame extending rearwardly beyond both said outer frame and the stationary mount,

first gear means in engagement with the arcuate gear racks, pg,l5

second gear means in engagement with said longitudinal gear racks, and

drive gear means in engagement with both said first and second gear means for pivoting said outer frame about said trunnions to position the recoiling gun parts to a desired elevation while simultaneously displacing said inner frame longitudinally relative to said outer frame to thereby shift the center of gravity of the combined cradle and the recoiling gun parts so that the changes in location of such center describe an involute arc radially disposed relative to the horizontal axis between said trunnions.

2. In a stationary gun mount having a traversing carriage provided with upwardly extending sidewalls, a cradle for pivotally supporting the recoiling parts of a gun between the carriage sidewalls, comprising,

an outer frame having a trunnion pin projecting outwardly from each side thereof into pivotal engagement with one of the carriage sidewalls,

an arcuate gear rack secured to each carriage sidewall forwardly of said trunnion pin,

an inner'frame having a longitudinal gear rack along each side thereof,

means for slidably seating said inner frame in said outer frame to extend rearwardly therebeyond and support the recoiling gun parts centrally between said trunnion pins,

a first pinion gear joumaled in each side of said outer frame to extend into meshing engagement with the corresponding arcuate gear rack on the carriage,

a second pinion gear joumaled in each side of said outer frame to extend into meshing engagement with said corresponding longitudinal gear rack on said inner frame, and

a driving gear engagement with both said first and second pinion gears for pivoting said outer frame about said trunnion pins to position the recoiling gun parts at a desired elevation and at the same time longitudinally displace said inner frame relative to said outer frame thereby shifting the center of gravity of the combined cradle and the recoiling gun parts along an involute path in a vertical plane passing through the center of the traversing carriage whereby the rear end of the recoiling gun parts is prevented from striking the base of the stationary mount when firing at the higher elevations thereof and whereby the overturning moment of the gun about the carriage is also substantially reduced.

t i i i 

1. A cradle for pivotally supporting the recoiling parts of a gun between a pair of spaced arcuate gear racks on a stationary mount, said cradle comprising, an outer frame having trunnions on each side thereof in pivotal engagement in the gun mount, an inner frame having a longitudinal gear rack along each side thereof, means for slidably seating said inner frame in said outer frame to support the recoiling parts of the gun centrally between said trunnions, said outer frame extending rearwardly beyond said trunnions and said inner frame extending rearwardly beyond both said outer frame and the stationary mount, first gear means in engagement with the arcuate gear racks, second gear means in engagement with said longitudinal gear racks, and drive gear means in engagement with both said first and second gear means for pivoting said outer frame about said trunnions to position the recoiling gun parts to a desired elevation while simultaneously displacing said inner frame longitudinally relative to said outer frame to thereby shift the center of gravity of the combined cradle and the recoiling gun parts so that the changes in location of such center describe an involute arc radially disposed relative to the horizontal axis between said trunnions.
 2. In a stationary gun mount having a traversing carriage provided with upwardly extending sidewalls, a cradle for pivotally supporting the recoiling parts of a gun between the carriage sidewalls, comprising, an outer frame having a trunnion pin projecting outwardly from each side thereof into pivotal engagement with one of the carriage sidewalls, an arcuate gear rack secured to each carriage sidewall forwardly of said trunnion pin, an inner frame having a longitudinal gear rack along each side thereof, means for slidably seating saiD inner frame in said outer frame to extend rearwardly therebeyond and support the recoiling gun parts centrally between said trunnion pins, a first pinion gear journaled in each side of said outer frame to extend into meshing engagement with the corresponding arcuate gear rack on the carriage, a second pinion gear journaled in each side of said outer frame to extend into meshing engagement with said corresponding longitudinal gear rack on said inner frame, and a driving gear engagement with both said first and second pinion gears for pivoting said outer frame about said trunnion pins to position the recoiling gun parts at a desired elevation and at the same time longitudinally displace said inner frame relative to said outer frame thereby shifting the center of gravity of the combined cradle and the recoiling gun parts along an involute path in a vertical plane passing through the center of the traversing carriage whereby the rear end of the recoiling gun parts is prevented from striking the base of the stationary mount when firing at the higher elevations thereof and whereby the overturning moment of the gun about the carriage is also substantially reduced. 